The determination of specific gravity or osmolality of liquids has long been recognized as a useful aid in the determination of solute concentration. In the clinical laboratory, the specific gravity or osmolality of body fluids, particularly urine, is a valuable aid in the diagnosis of many abnormal conditions such as kidney failure.
Various procedures and devices are described in the literature for the determination of specific gravity. For example, routine specific gravity determinations are made with hydrometers, pycnometers, gravitometers, urinometers, and the like. Although these prior art procedures are highly sensitive, they all require bulky instruments or devices which must be consistently cleaned, maintained and adjusted to produce reliable results. In addition, the prior art methods and devices require a relatively large sample volume and are time consuming. Therefore, it is considered highly desirable to provide a sensitive, rapid and reliable procedure and device for the determination of specific gravity or osmolality.